The major objective is to utilize restriction enzyme mapping to map the X-linked gene for blue cone monochromatism. The Center's extensive research on this genetic problem has produced perhaps the largest pedigree known containing 19 living affected males and 19 living carrier females. In this pilot project whole blood or frozen white blood cells will be sent to laboratories in Boston and New Haven where, under other support, mapping studies using restriction enzyme techniques will be performed. Our long term objective is to utilize the Center's extensive human pedigrees of many genetic disorders in collaboration with laboratories utilizing restriction enzyme procedures to map genes controlling eye disorders and their closely linked polymorphisms. Knowing the chromosomal location of genetic eye disorders and the polymorphic genes to which they are closely linked will have significant value in understanding the genetic organization of the genome, the linkage relationships in a segment around the locus, and perhaps the gene product of the abnormal allele. There will be significant value of this knowledge in genetic counseling and management of inherited eye disorders.